METHODS: Polymerase chain reaction primers were designed and validated to specifically amplify the cytosine that is followed by guanine residues (CpGs) A and B regions. Prior epigenotyping on 110 Kelantanese Malays, the serial pyrosequencing assays for the CpGs A and B regions were validated using five validation controls. The mean values of the DNA methylation profiles of CpGs A and B were calculated.

RESULTS: The mean DNA methylation levels for CpGs A and B were 0.984 ± 0.582 and 2.456 ± 1.406, respectively. The CpGs 8 and 20 showed the highest (5.581 ± 4.497) and the lowest (0.414 ± 2.814) levels of DNA methylation at a single-base resolution.

METHODS: The 114 healthy volunteers were recruited for this study, and their DNA was extracted. Primer pair was designed using Primer 3 Software version 0.4.0 and validated against the BLAST database. The primer specificity, functionality and annealing temperature were tested using uniplex PCR methods that were later combined into a single multiplex PCR. Restriction Fragment Length Polymorphism (RFLP) was performed in three separate tubes followed by agarose gel electrophoresis. PCR product residual was purified and sent for DNA sequencing.

RESULTS: The allele frequencies for MTHFR 677 C > T were 0.89 (C allele) and 0.11 (T allele); for eNOS +894 G > T, the allele frequencies were 0.58 (G allele) and 0.43 (T allele); and for eNOS -786 T > C, the allele frequencies were 0.87 (T allele) and 0.13 (C allele).

METHODS: This case-control study (n = 367) was conducted to investigate the correlation of the MTHFR gene polymorphism [NM_005957] and psoriasis vulgaris amongst the Malaysian population. Overnight fasting blood samples were collected from a subgroup of consented psoriasis vulgaris patients and matched controls (n = 84) for the quantification of homocysteine, vitamin B12 and folic acid levels.

RESULTS: There was no significant increase of the MTHFR 677 C > T mutation in patients with psoriasis vulgaris compared with controls (χ(2) = 0.733, p = 0.392). No significant association between homocysteine levels and MTHFR gene polymorphism in cases and controls were observed (F = 0.91, df = 3, 80, p = 0.44). However, homocysteine levels in cases were negatively correlated with vitamin B12 (r = -0.173) and folic acid (r = -0.345) levels. Vitamin B12 and folic acid levels in cases were also negatively correlated (r = -0.164).

MATERIALS AND METHODS: A total of 292 subjects were recruited, comprising 150 ischaemic stroke patients and 142 control subjects who were age and sex matched. Plasma homocysteine, serum folate and vitamin B12 were measured in all subjects. Genotyping was carried out using PCR-RFLP.

RESULTS: The homocysteine levels were significantly higher (P = 0.001) in the stroke group (11.35 ± 2.75 μmol/L) compared to the control group (10.38 ± 2.79 μmol/L). The MTHFR C677T genotype distribution for the stroke group was 46%, 40% and 14%, respectively for CC, CT and TT genotypes and 59.9%, 33.8% and 6.3%, respectively for the control group. The genotype and allelic frequencies were significantly different between the 2 groups, with P = 0.02 and P = 0.004 respectively. No significant difference was seen in the genotype distribution inter-ethnically. An increasing tHcy was seen with every additional T allele, and the differences in the tHcy for the different genotypes were significant in both the control (P <0.001) and stroke groups (P <0.001).

DESIGN AND METHODS: Data were obtained from the medical records and the laboratory information system. Paediatric patients with significant hyperhomocysteinemia were identified from a selective high-risk screening of 96,721 patients, performed between 2010 and 2022. Inclusion criteria for the study were paediatric patients with significant hyperhomocysteinemia (>40 µmol/L).

RESULTS: Sixteen patients were identified. The average total homocysteine (tHcy) and methionine were 269 µmol/L and 499 µmol/L in cystathionine β-synthase deficiency (CBS), 127 µmol/L and 29 µmol/L in patients with remethylation defects and 390 µmol/L and 4 µmol/L in congenital B12 deficiency. We found c.609G>A as the most prevalent mutation in MMACHC gene and possible novel mutations for CBS (c.402del, c.1333C>T and c.1031T>G) and MTHFR genes (c.266T>A and c.1249del). Further subclassification revealed CBS was 5/16 patients (31 %), remethylation defects was 9/16 (56 %) and congenital B12 deficiency was 2/16 (13 %). All patients received standard treatment and regular monitoring of the main biomarkers. The average age at the time of diagnosis were 9.2 years (CBS) and 1.2 years (remethylation defects). Congenital B12 deficiency had slight delay in milestones, remethylation defects had mild to moderate learning disabilities, CBS had variable degree of intellectual disability, delayed milestones, ophthalmological abnormalities, and thrombosis at an early adolescent/adulthood.